Preclinical EEG abnormalities in subacute sclerosing panencephalitis

Area of Science:

• Neurology
• Virology
• Neurophysiology

Background:

• Subacute sclerosing panencephalitis (SSPE) is a severe neurological complication of measles virus infection.
• Early diagnosis of SSPE is challenging due to its slow progression and variable presentation.

Observation:

• Persistent electroencephalographic (EEG) abnormalities were detected for 4 years prior to the clinical manifestation of SSPE in a subject initially considered a normal control.
• Initial EEG findings included focal paroxysmal discharges with evolving characteristics.
• Later, nonrepetitive generalized slow-wave complexes appeared during wakefulness, persisting for 3 weeks post-clinical onset.

Findings:

• Multifocal paroxysmal EEG discharges during the presymptomatic stage of SSPE were observed.
• These discharges likely originate from localized cortical areas with persistently infected neurons.
• The findings indicate that the brain remains responsive to viral presence even in a state of relative tolerance.

Implications:

• Presymptomatic EEG abnormalities can serve as potential biomarkers for early SSPE detection.
• Understanding early viral-induced neuronal dysfunction is crucial for developing timely therapeutic interventions.
• This case highlights the prolonged subclinical phase of SSPE and the utility of continuous EEG monitoring.